I can receive just fine, however, when I transmit on the radio, I cannot hear myself on my HT, nor can I hear when transmitting from the HT. It seems unlikely that I would not be able to transmit from both devices, but receive on both. This is all from indoors.

Several things I can think of:
Make sure the transmit and receive frequencies are the same. If you have a repeater frequency programmed into the transmit radio remember that it is transmitting on the repeater input frequency and the receiving radio is listening on the repeater output frequency. Try a simplex frequency on both radios. Next check to see that both radios have the same "tone" frequency for transmit and the same CTCSS frequency in receive. Better yet turn off the tone on both transmit and receive.

Several things I can think of:
Make sure the transmit and receive frequencies are the same. If you have a repeater frequency programmed into the transmit radio remember that it is transmitting on the repeater input frequency and the receiving radio is listening on the repeater output frequency. Try a simplex frequency on both radios. Next check to see that both radios have the same "tone" frequency for transmit and the same CTCSS frequency in receive. Better yet turn off the tone on both transmit and receive.

To repeat what was said above a different way, remember you are dealing with repeaters.
You transmit on one frequency and hear the repeater respond on another.
Both your radios must be programmed with the same transmitt/receive freqencies and PL enable tones.
If you do hear the repeater on the receiving set, chances are it could cause a feedback squeal if both sets are near each other.
The receive set will feed a signal back to the transmitt radio mike when keyed up.
To test on a single frequency, go to 146.515 or 525 and make the test by anouncing your call and the word testing.
Good luck.